Orthoptic instrument



1 1 1943- LE ROY WO'I'ITRING w 2,316,139

ORTHOPTIC INSTRUMENT Filed May 15, 1942 8 S heets -Sheet l INVENTOR. Le Roy WoH'ri'ng.

v ATTORNEYS LE ROY WOTTRING 'ORTHOPTIC INSTRUMENT pril 6, 1943.

Filed v 1942 \IIIIIII?///,

8 Sheets-she f 2 ATTORNEYS April 6, 1943. LE ROY WOTTRING Q 2,316,139

ORTHOPTI C INSTRUMENT Filed May 15, 1942 8 Sheets-Shet s mull;

INVENTOR. LczRoy Worrrmg.

ATTORNEYS April 6, 1943.

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A TTORNE Y5 April 6, 1943. LE ROY WOTTRING ORTHOPTIG INSTRUMENT Filed May 15, 1942 v s SheetsSheet e BY M VLML ATTORNEYS April 943. LE ROY WOTTRING 2,316,139

ORTHOPTIC INSTRUMENT Filed May 15, 1942 a Sheets-Shet 7 INVENTOR. LeRoy Wofriring'.

BYI PLM ATTORNEYS April 6, 1943.

LE ROY WOTTRING ORTHOPTIC INSTRUMENT Filed May 15, 1942 8 Sheets-Sheet 8 IN V EN TOR. A Le Roy WoH'n n9.

TTORNEYS Patented Apr. 6, 1943 ORTHOPTIO INSTRUMENT Le Roy Wottring, Altadena, Califi, assignor to The Wottring Instrument Company, Amherst, Ohio, a corporation of Ohio Application May 15, 1942, Serial No. 443,094

32 Claims. (.Cl. 128-765) My invention relates to an orthcptic instrument. It has to do, more particularly, with an orthoptic instrument of the general type known as an amblyoscope.

Various type of amblyoscopes have been provided in the past. The amblyoscope is basically a stereoscope of the well known Wheatstone type so mounted that the optical elements may be adjusted to the desired positions before the patients eyes. These prior art amblyoscopes are usually provided with means intended for making th necessary adjustments for the various pupillary distances or separations of various patients,

for measuring lateral or vertical deviations, as well as lateral or vertical ductions, and for measuring and testing cyclophorias and cycloductions.

Prior art amblyoscopes have been of a relatively fragile structure and become inaccurate after periods of time or use. Furthermore, they have usually been of such a nature that the re quired adjustments were difficult to make.v .It

has been practically impossible to obtain the de-.

sired range of prismatic effects because of limited adjustments provided on these prior art instruments. Furthermore, it has been impossible with,

these prior art instruments to obtain large amounts of prismatic elfects with narrow pupil-. lary adjustments. Also, with prior art instruments, limited working distances between the patients eyes and the targets has been an objectionable characteristic of these instruments, resulting in the well known phenomenon of psychic awareness of the nearness of the targets. Furthermore, theilluminating systems of these prior art amblyoscopes, for illuminating the targets, have not been entirely satisfactory for stimulating amblyopic patients. Also, efficient and effective means has not been provided in these prior art instruments for producing relative movement between the targets to stimulate vision of the amblyopic eye while training fusion. These prior art instruments have also been possessed of other objectionable features.

One of the objects of my invention is to provide an orthoptic instrument of the amblyoscope type which may be used for measuring ductions, measuring deviations from the true visual axis, measuring cyclophorias and cyclotropias, determining the presence of true or false projections, to determine the normal or abnormal correspondence of retinal points, and to determine'the absence or presence of and the degree of stereopsis.

Another object of myinvention is to provide an instrument of the type indicated in the preceding paragraph which is exceptionally advantageous for primary training of fusion, particularly in cases of squint, as well as the correction of many or all of the abnormalities named in the preceding paragraph. 7 7

Another object of my invention is to provide an amblyoscope which is of rigid construction such as to maintain accuracy over long periods of time and use.

Another object of my invention is to provide an amblyoscope of such a nature that the required adjustments may be made easily, quickly and accurately and the adjustments will be accurately maintained. i

Another object of my invention is to provide an amblyoscope capable of adjustment to the necessary extent to obtain thedesired range of prismatic effects. l v V Another object of my invention is to provide an amblyoscope of such a nature that it is possible to adjust the lenses closely together for narrow interpupillary distances without losing the desired prismatic effects. A

Another object of my invention is to provide an amblyoscope of such a nature that it may be adjusted to compensate 'for vertical deviations without losing part of the field of vision.

I provide an instrument which is based on Ficks 1 analysis of the movement of the eyeballs. According to Fick, the vertical axis of each eyeball is fixed with respect to the head. The hori-' zontal axis is perpendicular to the vertical axis and rotates aroundit. The line of sight is per pendicular to the horizontal axis and rotates around it. Torsional movements of the eye are rotations of the eye around the line of sight. The movement of the line of sight around the horizontal axis is described as a change of latitude. The movement of the horizontal axis around the fixed vertical axis is described as a change in longitude. In reality, the eye actually makes its movements on the principalof a ball turning in a pocket of fat, being controlled by muscles attached at various points, and 'to describe axes of rotation passing through the center of rotation is an arbitrary procedure.

My amblyoscope preferably comprises a' pair of tubes supported by suitable upstanding supports on a base. Each of these tubeshas an eye-i piece or lens at its inner end and a'target housing at its outer end. The inner or eye-piece por-' tions of the tubes are spaced apart laterally and are normally disposed substantially parallel. The outer portion of each tube extends at an 3. P. C. Southall Introduction t Ph l 1937,pp.'173174. ysmloglcal angle relative to the inner portion and these outer portions of the tubes are disposed in diverging relationship. To make it possible for the patient looking into the eye-pieces to see the targets, mirrors are provided in the tubes at the angles in the tubes. The targets used are preferably transparent targets and, therefore, lights are associated with the target housings behind the targets for illuminating the targets. The tubes are mounted independently of each other for movement about parallel vertical axes. They are also. independently mounted for movement about separate horizontal axes. adjusted to various positions in a vertical or horizontal direction, or both, and be held in the adT justed position. Means is also provided for adjusting the distance between the vertical axes to Thus, each tube ma be correspond to the interpupillary distance. The target housings are independently rotatableabout the axes of the outer portions of the tubes. A chin rest and brow rest are supported by the base for properly positioning the head of the patient relative to the eye-piece.

In using this instrument, the patient is seated before it and the chin rest and brow rest'are properly adjusted tov position the eyes relative to the eye-piece. The supports for the tubes are displaced laterally of each other until the eye-pieces are spaced apart the interpupillary distance of the'patient. The directions of the tubes can be independently adjusted both horizontally and vertically, if necessary, to compensate for lateral or vertical deviations and to permit the patient to fuse the targets. If necessary, the target housings can be rotated independently about the axes of the tubes to-compensate for cyclophoria. Suitable scales may be associated with the interpupillary distance adjusting means for making the interpupillary adjustment, with the horizontal direction adjusting means of the tubes for measuring lateral deviations, with the vertical direction adjusting means of the tubes for measuring vertical deviations, and with the rotatable target housings for measuring the cyclophorias or cyclofusional amplitude of the patient.

Thus, it will be apparent that, as previously stated, the instrument, is based on Ficks system of axes. When the head is associated with the instrument, the vertical axes, are fixed with respect to the head and the, horizontal axes are perpendicular to the vertical axes and rotate around the vertical axes, The instrument is so designed that the horizontal axis, about which the tubes can be adjusted in a vertical direction, and the vertical axis, about which each tube can be adjusted in a horizontal direction, are spaced a substantial distance in front of the centers of rotation of the eyeballs. With this arrangement it is possible to obtain greater prism displacement without interference between the forward portions or eye-pieces of the tubes when the in-. terpupillary distance is small.

The target-illuminating means provided on my machine is of such a nature that increased brilliance of illumination is obtained for greater visibility of targets to the amblyopic patient. Furthermore, the illuminating means is of such a nature that the lights for the two targets may be flashed independently of each other, simultaneously, or alternately, in order to overcome suppression.

A very important feature of my invention resides in the fact that the mirrors mounted in the tubes are mounted for movement in such a manner that it will appear to the patient that the targets have a lateral oscillatory movement. This simulation of lateral motion will stimulate perception in the amblyopic eye so that the moving image is visible to the amblyopic or suppressing eye, while the target in the other tube is simultaneously seen by the other eye. This type of primary fusion training not only develops simultaneous perception but indirectly increases visual acuity in the amb-lyopic eye. This simulated motion is obtained without disturbing the original setting of the tubes relative to the lines of sight; Furthermore, the means for moving the mirrors is of such a nature that the mirrors will always return to their exact original position. Thus, simulated motion is obtained without disturbing the original adjustment of the targets and as soon as this simulated motion is stopped, the patient will maintain perception with both eyes and will fuse the targets when training has progressed to this point.

The preferred embodiment of my invention is illustrated in the accompanying drawings wherein similar characters of reference designate corresponding parts and wherein:

Figure 1 is a perspective view of an instrument made according to my invention, the view being taken from the rear side or side opposite where the patients head is located.

Figure 2 is a front elevational view, partly broken away, of the instrument shown in Figure 1.

Figure 3 is a plan view of the. instrument illustrating by dottedlines how the horizontal adjustments of the tubes may be obtained.

Figure 4 is a vertical sectional view taken substantially along line 4-4 of Figure 3, illustrating by dotted lines how vertical adjustments of the tubes may be obtained.

Figure 5 is a horizontal sectional. view taken substantially along line 5-5 of Figure 2.

Figure 6 is a detail, in perspective, partly broken away, of the mechanism used for adjusting the tubes to compensate for difference in interpupillary distances and for adjusting the horizontal angular positions of the tubes.

Figure 7 is a vertical sectional view of a clamp-. ing element forming a part of the structure shown in Figure 6. a

Figure 8 is a side elevational view of the inner portion of one of the tubes illustrating the mechanism which I provide for operating the mirror carried within the tube.

Figure 9 is a horizontal sectional view taken substantially .along the-line 9--9 of Figure 8.

Figure 10 is ahorizontal sectional view taken substantially along the line !-l 0. of Figure 8.

Figure 11 is a schematic drawing of the power mechanism which I preferably use for oscillating the mirrors.

Figure 12 is a schematic drawing of the electric circuit provided for the target illuminating means of my instrument.

Figure 13 is a diagrammatic plan view of the instrument illustrating the position of the eyes relative thereto and illustrating various horizontal positions of the tubes.

Figure 14 is a diagrammatic side-elevational view of the instrument showing the position of upon which is disposed a pair of; tubes 2 These tubes are spaced apart latera1ly.' They ar so mounted, in a manner to be described hereinafter in detail, that they may be adjusted relative to each other laterally to vary the interpupillary distance therebetween, that they may be adjusted laterally to vary their horizontal angular positions, and that they may be adjusted vertically to various angular positions relative to the horizontal.

The base I is in the form of an inverted tray of substantially rectangular cross-section. With: in thisbaseis disposed most of the operating mechanism of the instrument.

Each of the tubes 2 comprises a light-proof portion 3 of substantially conical form with its smaller end forward, that is, towards the side of the instrument where the patients head will be disposed. At the forward end of this hollow conical portion 3 on eye-piece portion 4 is formed thereon. The axis of the portion 4 is disposed at an obtuse angle relative to the axis of the portion 3 as shown best in Figure 3. The eye-piece portion 4 is of annular cross-section at its forward end and has a spherical lens 5 mounted therein. In front of the lens 5 i a semi-circular socket portion 6 for receiving auxiliary plus or minus spherical lenses which may be required for some patients.

The rear end of the portion 3 of each tube is connected to a target and light housing I. This housing I embodies a forward target-receiving portion 8 and a rearward lamp-receiving portion 9. The portion 8 is provided with an opening in its forward wall corresponding to the opening in the rear end of th portion 3. Portion 8 is of substantially rectangular vertical transverse cross-section and is provided with guideways I (Figure 3) on the opposite side walls thereof which are adapted to receive the side edges of proper targets. These tar-gets will be translucent. Similar guideways II are provided in front of the guideways II! for receiving color filters which may be used if desired. Guideways I2 are formed behind guideways ID for receiving a target protecting member I4. For example, in Figure 3, I have illustrated a target I3 in position in the guideways I8 and a protecting member I4 in position in the guideways I2 behind the target. This member I4 is preferably formed of heat-resisting glass so it will protect the target from the heat of the lamp in the housing portion 9. The glass member I4 is preferably frosted so that it will serve as a light-diffuser for the target I3. The bottom of the housing I carries upwardly projecting socket member I for receiving an electric lamp I5a to which lid 8a is hinged. The bottom of the housing is provided with an air inlet opening Ia which extends from the front of the housing to a point behind the target, as shown in Figure 3. The rear end of housing I is of arcuate form. The target-receiving portion 8 of the housing is always covered by a hinged lid 8a and the lamp-receiving portion 9 is covered by a removable lid [1.

The lid 8a is of box-like form so the target I3 and member I4 can project up beyond the side walls of the housing (Figure 1) to facilitate removal of these members from the housing. An opening 8?) is provided at the rear edge of lid 8a to facilitate escape of heat from the housing. The lid IT has a dome portion I8 formedthereon which is provided with a heat-escape vent I9. Furthermore, the side walls of portion 9 are provided with a plurality of heat-radiating fins or ribs 20. I

In order to permit a patient looking through thelenses 5 into the eye-piece portions 40f the tubes ;2 to view the targets carried by the target housings I, I provide a mirror arrangement. This mirror arrangement comprises mirrors mounted in the tubes 2 at the junctions of the portions 3 with the portions 4, as shown best in Figure 9. Each mirror [3a is preferably of the first surface type. Itis disposed on the rear wall of the tube 2 and is disposed at such an angle that it will reflect an image of the target I3 and this image in the mirror can be seen by a patient looking into the eye-piece portion 4. The manner in which this mirror I3a is mounted will be discussed in detail hereinafter.

As shown best in Figures 2, 4 and 9, the housing portion 1 is rotatably mounted on the rear end of the portion 3. This is accomplished by providing the rear end of the portion 3 with a peripheral flange 2|. This flange 2I is disposed flat against the recessed forward wall 22 of the housing portion 1. This wall 22 is provided with screws at four points around the portion 3 which carry washers 23 that overlap the flange 2 I. Consequently, the housing I can be rotated on the rear end of the portion 3. As will be apparent hereinafter, rotation of the housing I relative to portion 3 will be desirable in order to rotate the targets relative to the lines of sight in compensating for cyclophoria or in testing the cyclofusional amplitude of a patient. A scale 24 (Figures 1, 2 and 3) suitably calibrated. is provided on a bracket 24a, secured to the side of housing I adjacent its forward end. A pointer 25 is car ried by the portion 3 of the tub and cooperates with the scale 24. The scale 24 is of arcuate shape having the center of its radius of curvature at the axis of portion 3. The scale 24 is provided with a zero mark 24b. When the housing I is in its normal position, indicated in the drawings, the zero mark of the scale 24 coincides with the pointer'25. The extent of rotation ofthe housing I in either direction will be indicated by the scale 24. i I

Each of the portions 3 of the tubes 2 carries a depending handle 26 adjacent its rear end. As will appear later, thes handles may be gripped by the hands in the adjustment of the tubes to various positions.

Each of the tubes 2 is carried by an upstanding bracket member 21 (Figures 1 and 2) which is carried by the base I. These brackets 21 are so disposed on the base I and are so connected to the tubes 2 that the eye-piece portions 4 of the tubes are normally disposed in laterally spaced substantially parallel relationship as shown 'best by the full line in Figure 3. Furthermore, the portions 3 of the tubes are normally in rearwardly diverging relationship. Each of the tubes 3 carries a forwardly projecting arm 28 (Figure 3). Each of the arms 28 has its rear end connected to the portion 3, substantially midway between the ends thereof, and each arm 28 is disposed substantially parallel to the eye-piece 4. The forward end of the arm 28 is pivotally connected by means of bolt 29 (Figures 2 and 3) to the upper end of the bracket 21. The tube 2 may be swung to any desired vertical position about the axis of the bolt 29, as shown by the dotted lines in Figure 4.

The arm 28 (Figure 2) carries an arcuate scale 30 which will move with the arm 28 but not relative thereto because of the pin connection 30a between the member 30 andthe arm 28. The calibrated arcuate outer flange 3| of the scale 36 has its-center of curvature at the axis of bolt 29. The bracket .21 carries-an upstanding pointer 32 (Figure .2) whichis immovably fastened thereto by a pin connection 132?). When the tube 2 is in exact horizontal position, the pointer 32 points at the zero on the calibrated flange 3| of the scale. Upon .swinging'of the tube 2 about the axis of bolt, the calibrated flange .3I swings about the axis of the bolt and the cooperating pointer 32 will indicate the extent of the movement of the tube -2 awayfrom horizontal position in'either'direction; As --will appear later, this adjustment of the two tubes relative to the horizontal is used to-compensate for vertical deviations in the sight of the patient.

Each of the tubes 2 is'adjusted'about thepivot point 26 and held in adjusted position by means of a screw 2%.. This screw is shownbest in Figures 4 and 14. It carries a knurled knob 2% on its lower end. Its upper end is threaded through a threaded opening formed in'a rearwardly projecting horizontal lug Tia-carried by the rear edge of bracket 21. The upper end of the screw engages a horizontally projecting lug 28a carried by the arm '28. Thus, it will be 'apparent that byoperating the screw 29a, the tube 2 may be swung upwardly or be allowed to swing downwardly about pivot point 29.

It will be noted from Figures land 2 that the vertical portions 33 of the brackets 21 are normally disposed adjacent the side edges of the base I. These brackets are provided at their lower ends with horizontal portions 34' which are connected to the vertical portions 33 by means of curve portions 35. The portions'34 of the brackets .21 extend inwardly to points towards the midpoint of base portion I and these points are closely adjacent .each other. At these points, the horizontal portions 34 of the brackets are connected by pivot structures-36 to the base 'I. It will be noted that the pivot structures 36 are disposed at the forward edge of the base I.

The pivot structures 36 are illustrated best in Figures 6 and '1. Each pivot structure is supported by the forward end of a horizontally disposed lever 31 which is disposed within the base I and is pivoted by means of a pin: 3:8 to the lower surface orf the'top plate '39 (Figure .2) of the base. A vertically disposed bushing '46 is provided which has its lower end rotatably disposed, as at M, in the lever 31. This bushing. extends upwardly through openings provided in a spacer 42 and in the horizontal portion 34 of brackets 21. The portions 34 and 42 are also free to rotate onthe bushing 40. A plate 413is .mounted for rotation on the. bushing '46 betweenthe member 31 and the member 4 2. Similarly a plate 44 is-mounted for rotation on the bushing 46 between the member 34 and the member 42 and is attached to the member-'34 (Figure -'7) for movement therewith about the bushing. L Thus, the plates 43 and 44 are disposed in spaced relationship. The plate 43 is disposed below the top plate 39 of base I (Figure. 2) and'the plate 44 is disposed above the top plate 39.

Passing through the bushing 40 is a pin 45 which is free to rotate therein. A handle member 46 iskeyed on the upper end of pin 45 and'is provided with a shoulder portion 41--whichrests on a boss 48 formed on the upper surface of members 34 around the opening which receives the bushing 40. The lower threaded end 49 of this-pin 45 cooperates with a threaded openingin a washer 50. This washer 50 fitsin a recess formed in the lower surface ofmember 31 and isprevented from rotating therein by means of pin 51. The bushing 46 terminates at its upper end at a point 52 short of the portion 41 and at its lower end ata point 53 short of the member 5.0. Itwill be apparent that rotating the member 46 in one direction will cause theshoulder portion 41 and the member 50 to move towards each other. Consequently, all or the members 34, 42, 43 and 31 will be clamped together and relative movement thereof about bushing 40 will be precluded. If the handle is rotated in the opposite direction, the member 56 and portion 41 will move "farther apart and the members 34, 42, 43 and 31 will be released so that relative movement will be permitted.

The plate 44 has an arcuate outer edge 54 which is suitably calibrated. The-calibrated portion 54a is provided with "a zero mark midway between its ends. The center of the arc-of curvature of the edge 54 of plate 441s at'the center of the pivot structure '36. The calibrated portion 540. cooperates with a mark 55 provided on the upper end of a pin '56 which projects upwardly from the plate 43 at the outer end thereof and is supported thereby. A link 51 has its 'forward end pivotally connected to the bottom surface of the plate 43, as at 56. The rear end of this link 51 is anchored by a pin 59 (Figure 4) to the lower surface of the top 39 of the base I. The distance between pivot points 58 and 59 is the same as the distance between pivot points 36 and 38. The link 51 is always disposed parallel to the forward portion 31w of lever 31.

The tubes 2 are initially in such position as to give the proper prismatic eifect for the normal patient, as shown by the full lines in Figure 3. When the tubes are in these angular positions, the zero marks on the calibrated portions of plates 44 will align with the marks 55 carried by the pins 56. However, if any adjustment of the angular positions of the tubes is necessary to dicate the amount of lateral deviations of the patients. In making these adjustments one or both of the handles 46 is turned to permit movement of one or both of the tubes about the pivots 36 as shown by the dotted lines in Figure 3. When the handle 46 'is turned in the proper direction, the bracket 2! may be swung about the pivot 36, as previously indicated, the plate 44 swinging with it about the pivot. The calibrated portion 54a of the plate '44 will swing relative to the marks 55 on the pins 56 and the amount ofthe horizontal angular adjustment of the tubes 2 will be indicated.

In order to adjust the interpupillary distance between the eye-pieceporti'ons 4 of the tube 2 to suit the requirements of the various patients, I provide the structure illustrated best in'F-igures 5 and 6. This structure is associated with the rear end of the levers 31. The rear end of each of these levers is pivotally connected by means of a pin 66 to a block '61 which is'provided with aninteiiorly threaded opening extending horizontally therethrough. The openings in the block 6| are adapted to receive oppositely threaded sections 62' of a horizontal shaft 63. The shaft 63 extends outwardly through the side wall of the base I and has a-knurled knob 64- on its outer end which iskeyed thereto and by means of which the shaft can be rotated. Intermediate its ends at a point between the levers 31 the shaft 63 carries a pair of spaced collars63a which are held in position on the shaft by means of set screws 63b. These collars are disposed between the oppositely threaded section of the shaft. The collars 63a are spaced from each other and between these collars a block 630 extends. This block is supported by pins 63d extending upwardly into the top 39 of the base I. Thus,.the stationary block 630 extends down between the collars 63a which are in a fixed position on shaft 63. Consequently, longitudinal movement of the shaft 63 is precluded although rotary movement of the shaft is permitted. When the shaft 53 is rotated in one direction, the rear end of levers 3'! will be moved towards each other.

When the shaft B3 is rotated in the opposite direction, the rear end of the levers 31 will be moved away from each other.

Movement of the rear end of the levers 37 towards or away from each other will swing the levers about the pivot point 38. This will move the pivot structures 36 closer together or farther apart. Consequently, it 'will move the brackets 21 towards or away from each other and will vary the distance between the eye-piece portions 4 of the tubes 2 as shown by a comparison of the full line and dotted line positions of Figure 15. During this adjustment links 51 will pivot about points 59 and plates 43 will pivot about member 40. This will keep plate 43 and pin 58 in proper cooperating relationship.

In order to indicate the distance between the eye-piece portions or, in other Words, in order to be able to duplicate the interpupillary distance of the patient, I provide a scale 65. This scale (Figures and 6) is secured to the upper end of one of the pins 50, as at 6E. The opposite end of the scale is calibrated, as indicated at 61, and fits within a notch formed in the upper end of the associated pin 63. The calibrated portion 61 cooperates with a mark 63 on the pin 60. As shown best in Figure 1, the scale 65 is disposed above the top 39 or the base. The pins 69 project up through arcuate slots 69 in the top 39 to permit the swinging movement of the pins durv ing adjustment of the rear ends of levers 31 by shaft 63. During the adjustment for the interpupillary distance each of the plates 43 and M will remain in a fixed relative position, the link 51 swingingaboutthe pivots 58 and 59 to permit the lateral movement of plate 43 caused by movement of lever 3'! about the pivots 38. The adjustment for interpupillary distance is made before effecting the angular adjustment of the tubes 2. The angular positions of the tubes 2 may be varied without affecting the setting of the eye-piece portions for interpupillary distance.

In order to position the head of the patient relative to the tubes 2, I provide (Figures 1, 2 and 4-) a chin rest structure and a brow rest structure H. The chin rest structure Til embodies a chin rest member 12 supported on the upper end of a pin 1'3. This pin 13 (Figure 2)-is splined forvertical movement in a sleeve portion 14 depending from the top 39 of the base. This portion M is located at the front edge of the base I midway between the side edges thereof. Consequently, chin rest- 12 will be located below the eye-pieceportions 4 of the tube 2 and somewhat forward thereoi, as shown best in Figures 3, 4 and 14. The pin 13 may be adjusted vertically to move the chin rest 72 to different elevationsrelative to the eye-piece portions 4 to suit various patients. This is accomplished by means of a lever disposed within the base i; (Figure 4).- -The lower end of pin 13 rests on the flat upper edge of lever 15 at the forward end thereof. The lever 15 is in the form of a bell crank lever and its rear portion is pivoted, as at 16, to a depending bracket 11 carried by the top portion 39 of base I. The short arm 18 of lever 15 extends downwardly and its rear edge is engaged by the forward end of a screw 19. This screw is threaded into a sleeve portion 89 carried by the rear wall of the base I. The screw extends through the rear wall and its rear end carries a knurled knob 8| which is keyed thereto. By means of this knurled knob 8|, the screw 19 may be. fed forwardly or rearwardly to swing the lever 75 upwardly or downwardly about pivot 16 and, therefore, to move the pin 13 upwardly or downwardly. This will move the chin rest 12 upwardly or downwardly. The chin rest 12 is keyed on the upper end of pin 13 and. the pin 13 is splined in sleeve 14 so that'there will be no rotation of member 12 about the axis of the pin E3.

The brow rest structure H (Figure 4) comprises a brow-engaging member 82. This member 82 is carried by a post or bracket 83. This post is secured to the top 39 of base I at a point adjacent the rear edge thereof (Figure 1) and substantially midway between the side edges of the base. It extends upwardly and is then curved forwardly above the level of the eye-piece portions 4 of the tubes 2. Consequently, the member 82 will be located above the eye-pieces 4 and between such eye-pieces. The member 82will be disposed forwardly in substantially the same plane as the pivot points 29 about which the tubes 2 are adjusted in vertical planes. The position of the brow rest 82 is illustrated best in Figures 4 and 14. Limited adjustment of the brow rest 32 forwardly 0r rearwardly is provided for by means of a sleeve-like portion 84 formed on post 83 which receives a pin formed on member 82. A set screw is provided on portion 84 for holding the member 82 in fixed position on the post 83.

When the patient is seated before the instrument, the chin rest structure It is adjusted to theproper elevation so that the patients eyes will be at the same level as the lenses 5 of the eye-piece portions 4 of the tubes 2. The. brow rest 82 may be adjusted forwardly or rearwardly slightly to engage the brow of the patient to prevent tilting of the head of the patient. The head of the patient will be positioned in the manner indicated in Figure 14. By means of the knob 64, the eye-piece portions 4 of tubes 2 will be adjusted towards or away from each other to'correspond to the interpupillary distance of the patient. This interpupillary distance will be indicated by the scale 65. When this adjustment is made the eyes of the patient will be positioned at the geometric centers of the lenses 5 as indicated in Figures 13 and 14. Either one or both of the tubes 2 is then adjusted vertically about the pivot 29 to compensate for vertical deviations if present. This adjustment is illustrated by the dotted line in. Figure 4. If the patient has vertical deviations in either eye, the extent and direction will be indicated. by the scales 3i! and cooperating pointers 32. If. the patient does not have any vertical deviations, this adjustment will not be necessary but the tubes i2 may remain in horizontal position. If the patient has lateral deviations, either one or both of the tubes 2 may be swung about pivot structures 36 to change the angular relationship of the tubes' The amount and direction of lateral deviations of either or both eyes of the patient will be indicated by the scales carried by plates 64; This adjustment is indicated best by the dotted lines in Figure 13. If the pa-' tient has cyclophoria in either eye, the target housing I may be rotated relative to portion 3 of the tube. When all of these adjustments have been made, the orthoptic training of the patient may begin. Furthermore, the various defects, and the amounts of each defect will be indicated to the orthoptist. All of the scales can be. read by the orthoptist from the rear of the instrument. Light for the scales will be supplied through openings Ia in housings I (Figure 3).

.Itwill be noted from Figures 13 and 14., that when the patient is properly positioned before the instrument, the pivot points 36 and the pivot points 29 will be spaced a substantial distance ahead of the centers of rotation C ofv the eyes of the patient. In other words, in adjusting the tubes 2 to compensate for lateral deviations of the patient, the tubes will be swung about separate vertical axes spaced a substantial distance ahead of the centers of rotation of the eyes of the patient while in adjusting the tubes 2 for vertical deviations of the patient, the two tubes.

will be swung vertically about separate horizontal axes passing through the pivot points 29 and which are disposed a substantial distance forwardly of the centers of rotation of the eyes. By means of this. arrangement I obtain several important advantages which will be apparent from Figures 13 and 14.

It will be notedfrom Figure 13, that the angular relationship of the portion 3 and the portion 4 of each tube 2 causes the portions 3 of the two tubes to diverge rearwardly. Consequently, it is possible to swing the rear ends of the tubes 2 towards each other through great distances to obtain great variations. in prismatic power without having the rear ends of the tubes contact with each other. Since the lenses 5 of the eyepiece portions 4 are spaced a substantial distance behind the pivot points 36, the eye-piece portions 4' may be adjustedclose together for narrow interpupillary distances, as shown by the dotted lines in Figure l3, and the tubes 2 can be swung about the pivots 36 to change the prismatic power,.as shownby the dotted lines in Figure 13, without. having the eye-piece portions l contact with each other and cause interference. It is possible to adjust the forward portion or eyepieces .4 of the. tubes close together to take care of narrow interpupillary distances Without losing desirable prismatic effects. Also, it is possible to adjust the tubes 2 to extreme vertical positions to compensate for extreme vertical deviationswithout losing part of the field of vision which would result if the targets alone were adjusted vertically on the tubes and relative to the lines of sight. Because of the adjustment which I provide for the interpupillary distance and the vertically adjustable chin rest which I provide, the eyes of the patient can be positioned so that the line of sight will be directly through the geometrical centers of the lenses 5. Thus, since theselenses are spherical, they will not produce a prismatic effect. Consequently, the horizontal and vertical positions of the tubes 2 will accurately indicate the amount of lateral and vertical deviations of the patient.

In order to stimulate perception of the amblyopic eye of the amblyopic patient and to obtain primary'training of fusion; I provide means" for obtaining simulated oscillatory motion of the two targets carried by the housings I. The simulated movement of the targets is obtained without disturbing the original adjustment of the tubes 2.

To accomplish this simulated motion, the mirrors I3a are mounted for oscillatory movement and I provide novel means for moving these mirrors. It will be noted from Figures 8 and 9 that themirror 53a. is carried non-rotatably by a shaft 86. This shaft extends vertically and is rotatably carried in bearing portions 91, which are disposed adjacent the top and lower edges of a boss 9i. This plate 88 covers an opening 89 in therear wall of the tube 2. The plate 88 has been removed in Figure 8. The plate 88 is adapted to be removably held in position over the opening 89 by means of screws 90; The opening 89 and the mirror l3a are of similar shape, as shown in Figure 3. As shown best in Figures 1 and 9, the plate 88 is secured to the boss 9|, which is formed around the opening 89 and projects rearwardly. This serves to provide a socket for the mirror l3a.

In order to move the mirror I3a about the axis of shaft 86, the shaft is extended downwardly below the lower bearing 87. The forward end of a horizontal arm 92 (Figure 10) is clamped to the lower end of the shaft 66 by means of clamping means 93. Secured to the side edges of the arm 92, by means of screws 94, at a point adjacent the forward end of the arm are a pair of leaf springs 95. These springs extend rearwardly in contact with the side edges of the arm 92' and beyond the rear end of the arm, as at 96. The extended portions 96 of the leaf springs straddle the cylindrical head 9'1 of a bolt 99. The bolt 98 is threaded upwardly into a boss 99 formed on the rear wall of portion 3 of tube 2 (Figure 1). A piston and cylinder unit I00 is secured by means of screws IOI (Figures 8 and 10) to the lower side of the portion 3. The unit I00 embodies a cylinder I02 (Figure 10) having a closed end I03 and an open end I04. It also includes a piston I05 having a piston rod I06 projecting outwardlythrough the open end I04. The piston I05 is slidably mounted in the cylinder I02 and is provided with a curved edge I01 which reduces friction and prevents a completely airtight fit between the cylinder and piston for a purpose to be explained hereinafter. The outer end of the piston rod I06 is pivotally connected as at I08 to the rear end of the arm 92.

Movement of the piston I in the cylinder I02 in either direction will swing the rear end of the arm 92 about the axis of shaft 86 and will therefore rotate the shaft 86. This will, consequently, swing the mirror I3a about the axis of shaft 96, as shown by the dotted lines in Figure 9. Swinging movement of the rear end of arm 92 in one direction will be resisted by the extension 96 of one of the springs 95 which will be in contact with the head 91 of bolt 98. Swinging movement of therear end of the arm 92 in the opposite direction will be resisted by the extension 96 of the other spring 95. Furthermore, it will be apparent that the springs will always return the arm 92 to its original position shown in Figure 10 whenever the moving force on piston I65 is released. As the piston rod I66 swings the rear end of the arm 92 in one direction against the resistance of one of the springs 95, such spring will be flexed outwardly away from the edge of the arm 92. To prevent flexing of either spring beyond its elastic limit, I provide a yoke member I09 which straddles the arm 92 adjacent its rear edge and which is secured thereto by means of a screw I I0. This yoke member I09 has depending arms III (Figures 1 and 10), which are spaced from the edges of the arms and limit outward movement of the springs 95.

In order to move the pistons I05 of the two units I00, I provide a diaphragm pump I I2. This pump H2 is disposed Within the base I at the rear end thereof and at one side thereof, as shown best in Figures 2 and 4. The pump H2 and the lines connecting it to units I are illustrated diagrammatically in Figure 11. The pump H2 comprises a housing H3 in which a diaphragm I I4 is disposed that divides the housing into chambers H5 and H6. diaphragm a rod H1 is connected to the center thereof and is slidably carried by a bearing H8 carried by the housing I I3. The outer end of this rod H1 is pivotally. connected as at H9 to one end of a link I20. This link I (Figures 2 and 4) is pivotally connected to the lower end of a pin I2I which depends from a horizontal lever I22. The forward end of the lever I22 is pivotally carried by the top 39 of the base I as indicated at I23. The rear end of this. lever extends through a slot I24 (Figures 1, 2 and 4) which is formed in the rear wall of base portion I. The pin IN is secured to lever I22 intermediate its ends. Thus, when lever I22 is oscillated, the rod II! will be reciprocated and the diaphragm I I4 will be flexed in both directions.

The chamber II5 of the diaphragm is connected by a line I25 to a valve I26. A line I21 runs from the valve I26 and is connected to the other chamber I I6 of the pump. A line I29 leads from the line I25 adjacent its connection to the pump and is connected to the closed end of the right-hand cylinder I02 (Figure 11). Similarly, a line I29 leads from the line I21 adjacent its point of connection to the pump and is connected to the closed end of the left-hand cylinder I02 (Figure 11).

The valve I26 comprises a tubular housing I30 having a cylindrical member I3I rotatably mounted therein and adapted to be rotated by means of a handle I32 (Figures 1 and 4) extending through the rear wall of the base I. The member I3I has a transverse bore I33 extending therethrough. The tubular housing I30 has a vent I34 disposed diametrically opposite a bore I35 formed in the housing and which communicates with line I25. A second vent I36 is provided in the housing I30 at a point diametrically opposed to the bore I31 formed in the housing which is in communication with the line I21.

Normally the valve is closed, that is, the member I3I will be in the position indicated by the full lines in Figure 11. At this time, the handle I32 will point straight downwardly (Figure 1). If the handle on the lever I22 is now oscillated, both units I00 will be actuated in order to move both mirrors I3a. When the handle of lever I22 is moved in a direction to move the diaphragm H4 to the right (Figure 11), pressure will be created in chamber H5 and vacuum will be created in chamber H6. Therefore, air will be forced through line I28 into the closed end of the right-hand cylinder I02 and will move the piston I05 to the left. Air will not be forced through line I25 since this line will be closed by the valve I26 at this time. The suction created in chamber H6 will act through line i29 on the closed end of the left-hand cylinder I02 and will draw the piston I05 to the left. At this time, the

For flexing the I05 to the left.

line I21 will not communicate with the atmosphere since it is closed by valve I26. When the lever I22 is moved in a direction such that the diaphragm II 4 moves to the left, pressure will be created in chamber H6 and vacuum will be created in chamber H5. The pressure will act through line I29 on the piston I05 of the lefthand cylinder I02 and will move the piston to the right. The vacuum in chamber H5 will act through line I29 on the piston I05 of the righthand cylinder I02 and will move it to the right. If it is desired to actuate one of the units I00 only, the valve I26 can be actuated. For example, if it is desired to operate the right-hand unit I00 without actuating the left-hand unit, the valve is rotated until the bore I33 in member I3I aligns with the bores I36 and I31. This will open the line IT! to the atmosphere. Consequently, when diaphragm H4 is moved to the right, pressure will, be applied through the line I28 to the right-hand cylinder I02 and will move the piston However, vacuum will not be produced in the chamber I I6 because the line I2! is opened to the atmosphere. Therefore, vacuum force will not be applied through line I29 to the left-hand cylinder I02. Consequently, the piston I05 in this cylinder will not be moved. If it is desired to operate the left-hand unit I00 only, the valve is rotated until the bore I 33 in member I3I aligns with the bores I34 and I35. This will openthe line I25 to the atmosphere. Consequently, when diaphragm H4 is moved to the right, pressure will not be applied through the line I20 because the line, I25 is opened to the atmosphere. Therefore, the piston I05 inthe right-hand cylinder I02 will not be moved. However, vacuum created in the chamber I I6 will act through the line I29 to move piston I05 disposed in the left-hand cylinder I02.

Thus, it will be apparent from the above that both pistons I05 may be moved in the same direction and at the same time. With the valve I 26 in closed position, both pistons will be reci procated simultaneously in the same directions. With the valve in either of its open positions, one of the pistons I05 will be reciprocated independently of the other. With this arrangement, the mirrors I3a may be oscillated simultaneously in the same direction or either mirror may be oscillated independently of the other. However, the springs will always serve to return the mirrors to their original positions so that fusion of the targets will :be restored. This is true regardless of the position of the oscillating lever I22. This is due to the fact that the pistons I05 have the curved edge I0! and fit in the cylinders I02 in such a manner that leakage past the pistons is permitted. This leakage will cause each piston to be. returned to its original position by spring 95 regardless of the position of diaphragm H4 and the resulting forces produced on the piston I05.

This simulated motion of the mirrors will stimulate perception in the amblyopic eye of the amblyopic patient so that the moving image is visible to the amblyopic or suppressing eye while the image of the other target is simultaneously seen by the other eye. This type of primary fusion training not only develops simultaneous perception but indirectly increases visual acuity in the amblyorpic eye. Vision of either eye may be stimulated .by the simulated movement of the corresponding target. The simulated motion is obtained without disturbing the original setting of the tubes 2 and as soon as the simulated mo tion is stopped, the patient will maintain perception with both eyes and will fuse the targets when training has progressed to this point.

In Figure 12, I illustrate diagrammatically the electric circuit I provide for the lamps 55a carried by the sockets I associated with the housings I. This circuit is of such a nature that it may be selectively actuated to maintain a constant illumination of both lights, flashing of both lights simultaneously, or flashing of the lights alternately. Also, the intensity of illumination of each light may be varied independently of the other. These features are desirable in connection with the orthoptic training of an amblyopic patient.

This circuit comprises the main lines I39 and I39 which are connected to a suitable source of power. The line I38 has a main control switch I40 associated therewith which is actuated by a lever I4I (Figure 1) carried by the back wall of base I. A line I42 leads from the switch I49 to a rheostat I43. A line I44 leads from line I42 to a rheostat I45. Rheostat I43 is connected by a line I49 to one of the lights I5a while rheostat I45 is connected by a line I4! to the other of the lights I5a. A line I48 is also connected to the one light I5a while a line I49 is connected to the other light I511. The line I48 leads to one movable contact member I59 of a double throw double pole switch I5I. The line I49 is connected to the other movable contact member I52 01 the switch I5I. The switch I5I is also provided with poles I53 and I54 adapted to contact with movable contacts I59 and I52, in one position of the switch, and poles I55 and I59 adapted to contact with themovable contacts I and I52, in another position of the switch. The poles I and I55 are connected together by a wire I51. The poles I54 and I56 are connected together by a wire I58. The pole I53 of the switch is connected by a wire I59 to one contact member I69 of a fiashnig switch I'6I. The pole I54 of the switch I5I is connected by a wire I92 to another contact member I63 of the switch I-EI. The switch I6I has a central contact I64 which is connected to line I39. All of the contacts I69, I63 and IE4 of switch I6! are spring contacts and they are all normally in contact, as indicated in Figure 12. The central contact I94 may be swung in either direction by means of a lever I65 which projects through a slot I66 (Figure 1) formed in the back wall of the base I. The switch I5I is actuated by a lever I51 (Figure 1) disposed on the back wall of base I.

In the use of this illuminating system, the main switch I49 is first closed to complete the circuit to both lights I5a. The rheostat I43 may be adjusted to control the illumination of the light I5a with which it is associated, that is, the righthand light in Figure 12. The rheostat I45 may be adjusted to control the intensity of the left hand light I-5a. Thus, the intensity or either light may be controlled independently of the other. In fact, either rheostat may be adjusted to interrupt completely the flow of current to the light with which it is associated.

The switch I5I, for example, may be in the position where the movable contacts I59 and I52 thereof connect the lines I48 and I49 to the lines I59 and I62, respectively. With the switch I5I in this position, when the lever I95 is oscillated, the lights will be flashed alternately. When the lever I65 is swung in one direction, the contact I64 will be moved away from the contact I53. This will break the circuit to th left-hand light I5a, while the circuit to the right-hand light I5a will be maintained because the contacts I64 and IE9 will still be in engagement. When the lever I55 is swung in the opposite direction, the contact I54 will be separated from the contact I60 and will break the circuit to the right-hand light I5a. However, the circuit to the left-hand light I511 will be maintained because contact I64 will still contact member I63 Thus, by oscillating the lever I95, the two lights I5a will be flashed alternately.

If the switch I5I is moved to its other position to cause the movable contacts I59 and I52 to contact poles I55 and I56 and connect line I92 to lines E48 and I49, when the lever I55 is oscillated, the lights I50. will be flashed on and ofi simultaneuosly. With the switch I5! in this condition, the lights are both normally on. When the lever I65 is swung in one direction, the contacts I64 and IE9 are separated. This will have no eiiect on the lights because members I63 and I64 are still in contact. However, when the lever I55 is swung in the opposite direction, the contacts I53 and I64 are separated, breaking the circuit to both lights I5a because connection between lines I39 and I62 is broken. At this time contacts I69 and I-64 will still be in engagement but no current will be supplied to the lights IEa because the line I59 is broken at the terminal I53, due to the position of switch I5I. Thus, by oscillating lever I65 :both lights may be flashed on and off simultaneously. However, if one of the rheostats is adjusted to interrupt supply of current to the light with which it is associated, such light will not be flashed.

Thus, the two lights may be flashed independently of each other, may be flashed simultaneously, or may be flashed alternately. This will be a great aid in overcoming suppression.

It will be apparent from the above description that I have provided an orthoptic instrument having many advantages. It may be used for measuring ductions, measuring deviations from the true visual axis, measuring cyclophorias and cyclotropias, determining the presence of true or false projections to determine the normal or abnormal correspondence of retinal points, and to determine the absence or presence of and the decrease or percentage of stereopsis. The instrument is exceptionally advantageous for primary training of fusion, particularly in cases of squint, as Well as the correction of many or all of the abnormalities named above. Stereograms may be employed in some phases of the training as targets but other types of targets may be employed in the initial phases.

My amblyoscope is of rigid construction so as to maintain accuracy over long periods of time and use. It is of such a nature that the required adjustments may be made easily, quickly and accurately and the adjustments will be accurate- 1y maintained. The instrument is capable of adjustment to the necessary extent to obtain the desired range of prismatic effects without interference between the two tubes.

Various other advantages Will be apparent from the preceding description, the drawings and the following claims.

Having thus described my invention, what I claim is:

1. An orthoptic instrument comprising a base portion, a pair of elongated hollow tubes so mounted on said base portion that a patient may look through the forward ends of such tubes, a translucent target mounted adjacent the rear end of eachof said tubes, a source of light in each of said tubes behind each target, an upstanding post for supporting each of said tubes on said base portion, each of said tubes being pivoted to said post adjacent its forward end for adjustment in a vertical plane, means for holding said tube in any position to which it is adjusted, a lever carried by the base for supporting said post, said lever being pivoted to the base for swinging movement in a horizontal plane, said post having a laterally extending arm pivotally connected to said lever adjacent its forward end, means for clamping said arm in any position to which it is adjusted relative to said lever, and means for adjusting the rear ends of said levers towards and away from each other and holding them in adjusted position. i

2. An orthoptic instrument according to claim 1' wherein said tubes comprise forward eye-piece portions and rear main portions which diverge outwardly and mirrors disposed at the junction of the eye-piece portions and the rear portions to permit view of the targets by the patient looking through said eye-piece portions.

3. An orthoptic instrument according to claim 1 wherein said tubes comprise forward eye-piece portions and rear main portions which diverge outwardly and mirrors disposed at the junction of the eye-piece portions and the rear portions to permit view of the targets by the patient looking through said eye-piece portions, said pivotal connections of the laterally extending arms of the posts to the forward ends of said levers and said pivotal connections of the tubes to said posts being disposed in front of theforward ends of said eye-pieces.

4. An orthoptic instrument according to claim 1 wherein a scale is associated with each of said pivots of the tubes to the posts to indicate the vertical positions thereof, with each of said pivot points of said laterally extending arms to the levers to indicate the lateral angular positions of the tubes, and with the rear ends of said levers to indicate the interpupillary distance between the eye-pieces of the tubes.

5. An orthoptic instrument according to claim 1 wherein said tubes comprise forward eye-piece portions and rear main portions which diverge outwardly, mirrors disposed at the junction of the eye-piece portions and the rear portions to permit view of the targets by the patient looking through said eye-piece portions, and means for moving said mirrors to simulate motion of said targets. 6. An orthoptic instrument according to claim 1 wherein said tubes comprise forward eye-piece portions and rear main portions which diverge outwardly, mirrors disposed at the junction of the eye-piece portions and the rear portions to permit view of the targets by the patient looking through said eye-piece portions, and means for moving said mirrors to simulate motion of said targets, said means serving always to return said mirrors to their original positions.

'7. An orthoptic instrument according to claim 1 whereinmeans is provided for flashing said lights.

8. An orthoptic instrument according to claim 1 wherein means is provided for flashing said lights alternately or simultaneously.

9. An orthoptic instrument according to claim 1 wherein means is provided for controlling the intensity of each of said lights.

10. An orthoptic instrument according to claim 1 wherein said tubes comprise forward eye-piece portions and rear main portions which diverge outwardly, mirrors disposed at the junction of the eye-piece portions and the rear portions to permit view of the targets by the patient looking through said eye-piece portions, means for moving said mirrors to simulate motion of said targets, and means for flashing the lights for said targets.

11. An orthoptic instrument according to claim 1 having a vertically adjustable chin rest disposed adjacent th forward ends of said tubes and supported by said base,

12. An orthoptic instrument according to claim 1 comprising a vertically adjustable, chin rest disposed adjacent the forward ends of said tubes and supported by said base, and a brow rest disposed at a level above said tubes and supported by the base for forward and rearward adjustment.

13. An orthoptic instrument comprising a pair of elongated hollow members so mounted that a patient may look through the forward ends of such members, a translucent target mounted adjacent the rear end of each of said members, a sourc of light in each of said members behind eachtarget, each of said elongated hollow members comprising portions disposed in angular relationship, mirrors disposed at the angles between said portions to permit viewing of the targets by a patient looking through the for-' ward ends of such members, means for mounting each of said mirrors for swinging movement about a vertical axis, and means for moving said mirrors about said axis to bring about simulated lateral motion of said targets.

14. An orthoptic instrument according to claim 13 wherein said means for moving, the mirrors always functions to return them to their original positions.

15. An orthoptic instrument according to claim 13 wherein said means for moving said mirrors comprises means selectively adjustable to move both of said mirrors simultaneously or one of said mirrors only.

16. An orthoptic instrument according to claim 13 wherein said means for moving the mirrors comprises manually operable means,

means for operatively connecting said manually operable means to the mirrors, said means comprises a unit selectively adjustable to move both of said mirrors simultaneously or one of said mirrors only.

17. An orthoptic instrument comprisingapair of elongated hollow members "so mounted that a patient may look through the forward ends of such members, a translucent target mounted adjacent the rear end of each of said members, a source of light in each of said members behind each target, each of said elongated hollow members comprising portions disposed in angular relationship, mirrors disposed at the angles be-' tweensaid portions to permit viewing of the targets by a patient looking through the forward ends of such members, each of said mirrors being carried by a vertically disposed shaft mounted for rotation, an arm carried by said shaft, and means for oscillating said arms to bring about simulated motion of said targets.

18. .An orthoptic instrument according to claim 17 wherein springs are associated with the arms to always return them to their original positions.

19. An orthoptic instrument according to claim 17 wherein each of said arms carries a pair of leaf springs on its free end which straddles an immovable member and which returns the arm to its original position.

20. An orthoptic instrument according to claim 17 wherein each of said arms carries a pair of leaf springs on its side edges which project beyond their free ends and which straddle an immovable member so that they will return the arms to their original positions, and a cylinder and piston unit associated with each of saidarms for imparting the desired movement to said arms. I I

21. An orthoptic instrument according to claim 1'? wherein each of said arms carries a pair of leaf springs on its side edges which project beyond the free end thereof and which straddles an immovable member so that they will return the arm to its original position, a cylinder and piston unit associated with each of said arms for imparting the desired movement to said arms, and a manually operable pump for controlling the supply of fluid to said units.

22. An orthoptic instrument according to claim 17 wherein each of said arms carries a pair of leaf springs on its side edges which project beyond the free end thereof and which straddle an immovable member so that they will return the arm to its original position, a cylinder and piston unit associated with each of said arms for imparting the desired movement to said arms, a manually operable pump for controlling the supply of fluid to said units, and means for selectively disconnecting said pump from either of said units.

23. An orthoptic instrument according to claim 17 wherein means is provided for flashing the sources of light for said targets.

24. An orthoptic instrument according to claim 17 wherein means is provided for flashing the sources of light for both targets simultaneously or alternately.

25. An orthoptic instrument comprising a pair of targets to be viewed by a patient, means permitting said targets to beviewed by the patient and including a pair of mirrors, means for mounting said mirrors for swinging'movement about vertical axes, means for moving said mirrors about said axis to bring about simulated lateral motion of said targets, and means for returning said mirrors to their original positions at all times when actuation of said last-named means is interrupted.

26. An orthoptic instrument according to claim 25 wherein said means for moving said mirrors is selectively adjustable to move both. of said mirrors simultaneously or one of said mirrors only.

27. An orthoptic instrument comprising a target adapted to be viewed by a patient, means for permitting said target to be viewed by the patient and including a mirror, means for mounting said mirror for swinging movement about a vertical axis, means for moving said mirror about said axis to bring about simulated lateral motion of said target, and means for returning said mirror to its original position whenever actuation of said last-named means is interrupted.

28. An orthoptic instrument comprising a pair of targets to be viewed by a patient, means permitting said targets to be viewed by the patient and including a pair of mirrors, each of said mirrors being carried by a vertically disposed shaft mounted for rotation so that the mirror can be oscillated laterally relative to the lin of sight, an arm carried by said shaft, means for oscillating said arm to bring about simulated lateral motion of said targets, and means for returning said arms to their original positions whenever operation of said last-nained means is interrupted.

29. An orthoptic instrument according to claim 18 wherein each of said arms carries a pair of leaf springs on its free end which straddles animmovable member and which returns the arm to its original position.

30. An orthoptic instrument according to claim 17 wherein manually operable means is provided for flashing the, sources of light for said targets, said means including a switch selectively operable to cause flashing of both of said lights simultaneously or alternately,

31. An orthoptic instrument comprising a pair of targets to be viewed by a patient,'means permitting said targets to be viewed by the patient and including a pair of mirrors, each of said mirrors being carried by a vertically disposed shaft mounted for rotation, an arm carried by said shaft, a cylinder and piston unit associated with each arm for oscillating said arm to bring about simulated motion of said targets, and means for returning said arms to their original positions whenever operation of said units is interrupted, said means comprising a pair of leaf' said shaft, a cylinder and piston unit associated with each arm for oscillating said arm to bring about simulated motion of said targets, and means for returning said arms to their original positions whenever operation of said units is interrupted, said means comprising a pair of leaf springs carried by each arm which project be yond the free end of the arm and which straddle an immovable member, and a manually operable pump for controlling the supply of fluid to said units.

LE ROY WOTTRING. 

